modded-nanogpt medium world record: Re-using intermediate activations in the output latents

Adding the output of layer 11 to the final output latents in a learned, weighted sum leads to a separation of concerns for early model layers: it enables them to focus only on providing context to the next layer, without directly impacting the final prediction. Backing them out of the residual stream this way improves model performance and led me to a new modded-nanogpt medium track world record.